shell/math: code shrink

function                                             old     new   delta
arith_apply                                         1023     996     -27

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 13 insertions, 11 deletions

diff --git a/shell/math.c b/shell/math.c
index e15b014aa..5b996703e 100644
--- a/shell/math.c
+++ b/shell/math.c
@@ -313,8 +313,10 @@ arith_lookup_val(arith_state_t *math_state, const char *name, char *endname)
 }
 
 /* "Applying" a token means performing it on the top elements on the integer
- * stack. For an unary operator it will only change the top element, but a
- * binary operator will pop two arguments and push the result */
+ * stack. For an unary operator it will only change the top element,
+ * a binary operator will pop two arguments and push the result,
+ * the ternary ?: op will pop three arguments and push the result.
+ */
 static NOINLINE const char*
 arith_apply(arith_state_t *math_state, operator op, var_or_num_t *numstack, var_or_num_t **numstackptr)
 {
@@ -337,9 +339,9 @@ arith_apply(arith_state_t *math_state, operator op, var_or_num_t *numstack, var_
                         return "malformed ?: operator";
                 if (expr1->val != 0) /* select expr2 or expr3 */
                         top_of_stack--;
-                expr1->val = top_of_stack->val;
-                expr1->var_name = NULL;
-                return NULL;
+                rez = top_of_stack->val;
+                top_of_stack = expr1;
+                goto ret_rez;
         }
         if (op == TOK_CONDITIONAL) /* Example: $((a ? b)) */
                 return "malformed ?: operator";
@@ -469,13 +471,13 @@ arith_apply(arith_state_t *math_state, operator op, var_or_num_t *numstack, var_
                         math_state->setvar(top_of_stack->var_name, buf);
                         *e = c;
                 }
-                /* After saving, make previous value for v++ or v-- */
-                if (op == TOK_POST_INC)
-                        rez--;
-                if (op == TOK_POST_DEC)
-                        rez++;
+                /* VAR++ or VAR--? */
+                if (PREC(op) == PREC_POST) {
+                        /* Do not store new value to stack (keep old value) */
+                        goto ret_NULL;
+                }
         }
-
+ ret_rez:
         top_of_stack->val = rez;
  ret_NULL:
         /* Erase var name, it is just a number now */